XML 59 R45.htm IDEA: XBRL DOCUMENT
v2.4.0.8

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Part 1 (Details) (USD $) In Millions, unless otherwise specified | 12 Months Ended
--- | ---
Sep. 30, 2013 customer | Sep. 30, 2012 | Sep. 30, 2011
Nature of operations [Abstract] |  |  |
Population of service area (more than) | 1,130,000 |  |
Utility Plant, Depreciation and Amortization [Abstract] |  |  |
Average annual depreciation and amortization expense percentage | 3.20% | 3.10% | 3.10%
Annual capital expenditures | $ 128.5 | $ 106.7 | $ 67.3
Accruals for capital expenditures | $ 4.7 | $ 9.7 | $ 8.2

X
- Definition Annual capital expenditures. + References No definition available. + Details
Name: | lg_AnnualCapitalExpenditures
Namespace Prefix: | lg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Population (approximate) amount in the greater geographic region served by the company's gas operations. + References No definition available. + Details
Name: | lg_ApproximatePopulationOfServiceArea
Namespace Prefix: | lg_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition The average annual depreciation and amortization expense as stated as a percentage of original cost of property. + References No definition available. + Details
Name: | lg_AverageAnnualDepreciationAndAmortizationExpensePercentage
Namespace Prefix: | lg_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | lg_NatureOfOperationsAbstract
Namespace Prefix: | lg_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | lg_UtilityPlantDepreciationAndAmortizationAbstract
Namespace Prefix: | lg_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Future cash outflow to pay for purchases of fixed assets that have occurred. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4332-108586 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4313-108586 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586 + Details
Name: | us-gaap_CapitalExpendituresIncurredButNotYetPaid
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration